This circuit with TTL compatible output was found in a 1968 US documentation. The circuit is powered by 5 V and the frequency can be changed by changing the crystal.
This oscillator does not carry any resonant circuit, except for the one formed by the crystal...
This is the circuit of a small commercial amplifier from the 1970s from Philips Argentina. The...
This powerful high-fidelity amplifier was described in an article in Radio Electronics magazine in...